Energy absorption and distribution material

ABSTRACT

An energy absorbing and transmitting material comprising a framework of interconnected units comprising at least one unit having a base and a protrusion or cone extending from the base along an axis, and at least one connecting member or rod that connects the unit to at least one adjacent unit, the connecting members extending substantially perpendicular to the axis of the unit from the base, where the framework is comprised of a single elastic material throughout, or configured so that when the framework is perturbed by tilting the unit towards the adjacent unit, the adjacent unit is tilted towards the unit.

CROSS-REFERENCE TO RELATED APPLICATIONS

This application claims priority to Canadian Patent Application No.2,666,411 filed May 20, 2009, entitled “Energy Absorption andDistribution Material,” which application is incorporated by referenceherein in its entirety.

FIELD OF THE INVENTION

The present invention relates to a material for absorbing anddistributing kinetic energy for use in bearing loads or absorbingimpacts or vibrations.

BACKGROUND OF THE INVENTION

Various materials may be used to absorb or dissipate energy from animpact, vibration or load which would otherwise be transmitted to anunderlying structure or body. Such materials are used in a wide varietyof applications where such absorption or dissipation is desirable, forexample, in sporting equipment for contact sports, building materials,sound proofing materials, seating cushions or automobiles.

A common impact absorption apparatus is a sheet of material having auniform thickness made of an elastic foam or rubber. A sheet of plasticfoam may act as a cushion, absorbing some energy from a load or impactby the compression of the material, so less energy is transmittedthrough the material to the underlying structure.

There are a number of drawbacks for these impact-absorbing devices.Specifically, these devices typically rely on compression as the mostimportant mechanism for reducing the transmission of force from animpact or load to any underlying structure. Consequently, theireffectiveness in absorbing energy from impacts or loads is largelydictated by the thickness of the impact-absorbing material and itselasticity and density.

The required thickness of the impact-absorbing material in a moldedpiece device gives rise to a number of undesirable properties. Whenwearing such a device, the wearer's range of motion may be restrictedbecause the thickness of the material required for effectiveimpact-absorption reduces the flexibility of the device. The materialstypically used are also typically limited in elasticity, furtherreducing flexibility. In addition, the thickness and coverage of themolded piece device limits the airflow between molded piece device andthe body, causing body heat to be undesirably retained. The ability tomake such a device lightweight is also limited by the dependence on thethickness of the material.

Such devices are typically only suitable for a relatively small range ofimpact forces, as the material will not provide the appropriateresistance outside of that range. Thin low density material does notgenerally provide sufficient energy absorption in an application wherehigh-energy impacts are expected.

On the other hand, dense materials must be used with caution because ofthe possibility of injury or damage to the underlying material if theyare too dense or rigid. Thus, in many applications, these devices tendto be less flexible or heavier than desirable because of the thicknessrequired for a low enough density material to provide sufficientresistance in the case of an impact.

There are devices that include structural features and the use ofcomposites to absorb energy. For example, there are materials whichcomprise two impact absorbing materials of different densities that arelayered and held together by physical means, adhesives or welds. Asofter, lower density material layer may present a more forgivingsurface for body contact, while a denser, harder material layer providesmore resistance at a reduced thickness. There are also materials thatcomprise a composite structure having a plurality of cones affixed ontoa semi-rigid or rigid substrate of a different material.

While these devices provide some advantages over sheets of plastic foam,these devices rely on compression as the most important mechanism forreducing the force from impacts. Consequently, the effectiveness ofthese devices is dictated primarily by the thickness of the materials.Since the effectiveness of the devices generally depends on the amountand density of material present in the device, the ability to achieve alightweight and flexible device is limited.

There is a need for an impact-absorbing structure that is flexible,lightweight and not bulky, and that responds differently depending onthe level of force applied.

SUMMARY OF THE INVENTION

The present invention relates to an energy absorbing and transmittingmaterial comprising a framework of interconnected units comprising:

at least one unit having a base and a protrusion extending from the basealong an axis, and

at least one connecting member that connects the at least one unit to atleast one adjacent unit, which extends substantially perpendicular tothe axis from the at least one unit proximate to the base,

wherein the framework is comprised of a single elastic materialthroughout.

The present invention also relates to an energy absorbing andtransmitting material comprising a framework of interconnected unitscomprising:

at least one unit having a base and a protrusion extending from the basealong an axis,

at least one adjacent unit adjacent to the at least one unit having asecond base and a second protrusion extending from the second base alonga second axis, the second axis substantially parallel to the axis whenthe framework is at rest,

at least one connecting member that connects the at least one unitproximate to the base to the adjacent unit proximate to the second base,which extends substantially perpendicular to both the axis and thesecond axis between the units when the framework is at rest,

wherein the at least one connecting member is elastic, and when theframework is perturbed such that the at least one unit is tilted towardsthe adjacent unit by a force applied to the protrusion offset from theaxis at an angle greater than 0 degrees and less than 90 degrees, theadjacent unit is tilted towards the unit.

The invention may further relate to the material described above,wherein the protrusions each have a tip extending from the protrusionsalong the axis, the tips being the same or differently sized or shaped.

The invention may further relate to the material described above,wherein the at least one unit further comprises at least one baseprojection extending from the base, or two or more base projectionsextending from the base and spaced apart and arranged on the base.

The invention may further relate to the material described above,wherein the at least one unit and the at least one adjacent unit havediffering densities, different shapes, or sizes, or further comprises atleast one additional unit proximate to the unit and the adjacent unit inthe framework having a different density, size or shape than the unitand the adjacent unit.

BRIEF DESCRIPTION OF THE DRAWINGS

Embodiments of the invention will be described by way of example andwith reference to the drawings in which:

FIG. 1 is a cross sectional view of units in one embodiment of thecurrent invention.

FIG. 2 is a top view of a framework of units of FIG. 1.

FIG. 3 is a bottom view of the framework shown in FIG. 2.

FIG. 4 is a top perspective view of the framework of FIG. 2.

FIG. 5 is a bottom perspective view of the framework of FIG. 2.

FIG. 6 a is a cross sectional view of connected units in anotherembodiment of the invention.

FIG. 6 b is a top view of a framework of units of FIG. 6 a.

FIG. 7 is a top view of a framework in another embodiment of theinvention.

FIG. 8 a is a cross sectional view of a unit according to the invention.

FIG. 8 b is a perspective view of a framework of units of FIG. 8 a.

FIG. 8 c is a top view of a framework of units of FIG. 8 a in anotherembodiment of the invention.

FIG. 8 d is a top view of a framework of units of FIG. 8 a in anotherembodiment of the invention.

FIG. 9 is a side view of a unit according to another embodiment of theinvention.

FIG. 10 is a perspective view according to another embodiment of theinvention.

DETAILED DESCRIPTION

FIG. 1 shows a section of one embodiment of the present invention. Aunit (1 or 2) comprises a base (4 or 5) and a protrusion (6 or 7)extending upwardly from the base (4 or 5). Adjacent units 1, 2 arejoined together by at least one connecting member 3 at or near the base4, 5 of each unit 1, 2 to form a framework.

In this preferred embodiment, each unit 1, 2 comprises a tip 8, 9positioned at the uppermost portion of the protrusion, and at least onebase projection 10, 11 extending downwardly from each base 4, 5. Inother embodiments, the tips, the base projections, or both may beomitted.

Protrusion 6, 7 extends upwardly from the base 4, 5 along a verticalaxis. The protrusion 6, 7 may compress under a load, and may also tendto deflect away from a vertical orientation when under load. In thepreferred embodiment shown, the protrusions 6, 7 are conical.

In this preferred embodiment, bases 4, 5 are rounded in a hemisphericalshape. At least one base projection 10, 11 may extend downwardly fromeach base 4, 5 to reduce contact between the units and any underlyingsurface. The shape of the base 4, 5 and the positioning and shape of thebase projections may also be selected to increase the tendency ofcertain units to tilt relative to adjacent units.

In an impact, the units 1, 2 may both compress and deflect, therebydissipating the energy along connecting members 3. Under load, some ofthe units will tend deflect or tilt relative to other adjacent units.

The deflection of any particular unit 1, 2 will cause energy to betransferred to other units in the framework by bending and pullingmotions through connecting members 3 and other units not immediatelyadjacent to the units 1, 2. Connecting members 3 are preferably joinedto the units 1, 2 to allow the deflection of the units to occur in animpact. Preferably, connecting members 3 will be joined to the units 1,2 at or near the base 4, 5, and may be located where the base 4, 5, andthe protrusion 6, 7 meet, thereby causing units and adjacent units totilt towards each other when one is deflected or tilted.

Each unit 1, 2 may also comprise a tip 8, 9 positioned at the uppermostportion of the protrusion 6, 7. By frictional contact with a surface,the tip 8, 9 will tend to deflect when presented with an impact toeffectively absorb vibrations and concussive forces of lower energy. Thetip 8, 9 may also aid in the deflection of protrusion 6, 7 at higherimpact forces. Although the heights of protrusions 6, 7 do not have tobe identical, it is preferable that all of the tips grouped at the areaof impact will experience deflection at the impact.

The tips 8, 9 may be shaped differently or have a different density thanthe underlying protrusions 6, 7 such that the tips 8, 9 are relativelymore likely to deform under load than the underlying protrusions 6, 7.For example, as shown in the figures, the tips 8, 9 may be cylindrical,placed upon conical protrusions 6, 7. The tips 8, 9 are more likely todeform than the conical protrusions 6, 7 if they experience any loadsthat are not straight downwards onto the tips 8, 9, and will typicallybend under such loads.

In FIG. 2, units 1, 2 are joined to each other and to other units by atleast one connecting member 3 to make a framework or web of connectedunits 12. The base of protrusion 6, 7 may be circular, and the base ofprotrusion 7 may be of a larger diameter than base of protrusion 6.

In a preferred embodiment, the narrower unit 1 and the wider adjacentunit 2 are arranged to alternate from each other in framework 12. Theunit and the adjacent unit may be identical in size, shape and density,or may differ in any one or all of those properties.

In an alternative embodiment, there are three or more units of differingsizes, shapes or densities in the framework. In this alternativeembodiment, the sizes, shapes and densities of the units could be variedacross a framework to accommodate differences in the loads anticipatedin various areas of the framework. For example, in an application wherean underlying structure has a delicate or sensitive area, and has one ormore points surrounding the delicate area that are more robust, aframework could be adapted with smaller or less dense units over thesensitive area, and larger or more dense units over the robust areas.This may serve to focus loads applied to the entire framework on themore robust points, and comparatively less on the delicate portions.

Another example would be to use differently sized or shaped units tobetter deflect impacts that are more focused, in that they apply forceto the framework over a smaller portion of the framework. Smaller unitscould be employed in those regions where more focused impacts or loadsare expected.

The difference in compression and deflection properties between the unitand the adjacent unit may result in a framework that resists moreresponsively to varying levels of force. The narrower unit 1 may tip ortilt more readily than the wider adjacent unit 2. The addition of thetips 8, 9 may add additional capability of the framework 12 to dissipateenergy, as the deformation of the tips 8, 9 absorbs some energy, andincreases the tilting of the units 1, 2 throughout the framework 12,thereby dissipating additional energy.

When the unit 1 and the adjacent unit 2 are tilted towards each otherunder a load, when the amount of the load increases, the units willdeflect further to a certain degree, but will also increasinglycompress. Under larger sustained loads, the units will have completelydeflected, resting on each other, on connecting members, or on theunderlying structure. Under these circumstances, the material willbehave like a uniform sheet of foam, continuing to compress under thesustained load. Preferably, the material is elastic, so that when theload is removed, the units resume their original positions relative tothe framework.

In other embodiments according the present invention, the differentsizes of units may be in other regular arrangements within theframework. For example, one large or wide unit may be placed as everythird, fourth, fifth, etc. unit with all other units being smaller ornarrower units in each row. In other embodiments, the different sizes ofunits may be arranged irregularly to accommodate expected loadsappearing in particular locations of the framework, or entirely randomlythrough the framework. In alternative embodiments, any one or all of theprotrusions 6, 7, the bases 4, 5, the connecting member 3, the tips 8, 9if present, and the base projections 10, 11 if present, may be of thesame or different sizes, shapes, densities or materials.

It is preferable that the same material is preferably used throughoutthe framework. Using the same material throughout may be desirablebecause the material can be easily molded or shaped as a singlecontinuous sheet, thereby making it easier to manufacture. In oneembodiment, the material is molded in an injection or compression mold.

Also, while the same material is preferably used throughout theframework 12, the density of the materials in each of the various unitsmay be controllably varied from each other in order to vary theimpact-resistance profile. As with size, alternating the density in theframework 12 may result in a wider range of responsiveness to appliedforces because of the difference between the compression and deflectionproperties. In other embodiments, protrusion 6 may be of a higher orlower density than protrusion 7, tip 8 may be of a higher density orlower than protrusion 6, and/or tip 8 may be of a higher or lowerdensity than tip 9. In this embodiment, it is possible to vary thedensity of certain elements of the framework by injecting relativelymore material into the mold in those points where a higher density isdesired.

For example, in an embodiment having a unit and corresponding tip havinga higher density than an adjacent unit, the higher density unit iscomparatively more rigid, and may be more likely to tilt under aninitial load. As the load increases, the softer units will bear the loadin compression as the comparatively denser units tip over until they arefully deflected. Once fully deflected, the comparatively dense unitswill also bear the load in compression, thereby providing additionalresistance to the increased load. In this example, the material iscapable of responding non-lineally to a range of loads, or a changingload, as a function of the differing densities and the particularstructure of the framework of units. The size, shape and density of theunits could be tailored to fit a variety of different potential loadcurves.

FIG. 3 shows the arrangement of units in framework 12 as viewed from thebottom. Each unit may independently have one or multiple baseprojections 10, 11. Further, the base projections 10, 11 can vary insize. The base projections 10, 11 may be arranged so that a unit iscomparatively more likely to deflect or tilt relative to an adjacentunit. This may be achieved by arranging a number of base projectionsaround the base in a square, triangle or other regular polygonalarrangement to provide a relatively stable platform on the unit, and asingle or an irregular arrangement of base projections on the adjacentunit to provide an unstable platform.

FIGS. 2 and 3 also depict four connecting members 3 arranged at 90degrees around each unit f, 2 resulting in a framework that is organizedin a square grid. In other embodiments of the invention, units may bejoined together with varying numbers of connecting members, and theconnecting members connected to a particular unit may be offset fromeach other at different angles. The frameworks in such embodiments wouldbe different geometric arrangements, for example, as triangular orhexagonal grids.

The top structure of the framework of the same embodiment is shown inFIG. 4. In an impact, tips 8, 9 may dampen vibrations and cause theframework to move congruously with the forces of impact. At greaterforces, one or a group of units 1, 2 will bend against the connectingmembers 3, which causes energy to be diffracted and dissipated alongthese connecting members.

As depicted in FIG. 5, bases 4, 5 are preferably rounded to form ahemispherical structure to minimize contact with the underlying contactsurface (not shown) below the framework. The hemispherical shape ofbases 4, 5 may allow air flow through the framework to be maximized andenhance the ability of the units 1, 2 to tip and roll relative to eachother.

Base projections 10, 11 may further minimize contact between theframework 12 and the contact surface. When structured in this manner,the bases 4, 5 may also aid in absorbing impact by compressing to allowmore bending of connecting members from perpendicular downward forces.This bending both absorbs and spreads the energy through the framework.

The protrusions may be any shape capable of bearing a load. In otherembodiments, the protrusion may be formed in any suitable shape orshapes for bearing load in compression, such as frustocones,hemispheres, ovoids, cylinders, any polyhedron, or any shape that taperstowards the top.

For example, FIG. 6 a shows another embodiment of the invention in whichthe protrusions are differently shaped. The unit 101 comprises of aninverted annular trough shaped base 104 which connects to a conicalprotrusion that is open from the bottom 106. As force is applied to theprotrusion 106, the unit 101 may compress asymmetrically. Bending andpulling motions of the unit 101 through the base 104 transfers theenergy from an impact through connecting members 103 to the other units.

FIG. 6 b depicts an example of how the units in FIG. 6 a may be joinedin a framework 112. It should be noted that there are manyconfigurations for connecting members to be connected to units. In FIG.6 b, each connecting member 113 is connected to four units separated by90 degrees, giving the appearance that one connecting member“intersects” with another.

FIG. 7 shows that units may be joined together in framework 212 wherethe connecting members 203 separated at 60 degrees on each unit. As aresult, the connecting members 203 are aligned on three axes 150, 160,170. In other embodiments, there may be different numbers of connectingmembers connected to each unit, and the connecting members connected toa particular structural unit may be offset from each other at differentangles.

Returning to FIG. 7, connecting member 203 may be tapered at theconnections with the units. In other embodiments, the dimensions of aconnecting member may be varied in other ways according to theapplication and the properties desired. For example, the length and/orthickness or diameter of connecting member may be varied according tothe properties desired. While thicker, shorter connecting members may beused to transfer energy more effectively and resist higher impacts,narrower connecting members can provide greater elongation andflexibility, and the resulting framework would also be lighter and allowmore air flow. Connecting members may also be curved, or tapered at oneor both ends. Different densities are also possible. Further, a mix ofdifferent connecting members may be used in a particular framework todirect forces to a particular area of the framework.

FIG. 8 a depicts another embodiment of a unit according to theinvention. The unit 301 comprises an annular base 305 from which theprotrusion 306 comprises multiple supports 316 projecting from the base305. Tip 308 is at the intersection where the multiple supports 316intersect within the ring drawn by the base 305.

In FIG. 8 b, the multiple supports 316 of a unit 301 form ahemispherical protrusion 306 above the base 305. Tip 308 is suspended atthe top of the protrusion 306, where the multiple supports 316intersect.

FIG. 8 c shows how the units of 8 a may be joined to form a framework312. Rather than being joined by connecting members, units 301 arejoined by direct contact between the bases 305. In this embodiment, theunits 301 may be arranged along three axes at 60 degrees from each other250, 260, 270 in the framework 312.

The units may also be connected by both direct contact and connectingmembers 323, 333. There may be primary connecting members 323 that mayeach connect to multiple units, and there may also be secondaryconnecting members 333 that curve.

FIG. 9 depicts another possible unit shape. The protrusion 406 in thisunit 401 comprises two supports 416 projecting from the annulus base405. A tip 408 sits at the apex of protrusion 406 where the two supports416 meet.

The present invention is particularly suited to uses in sports equipmentsuch as helmets, chest protectors, shin guards and pads because it isflexible, light-weighted, hygienic, customisable and possesses acontinuous impact-resistance profile and maximizes air flow. For theseapplications, the framework of structural units may be made to conformto a particular three-dimensional shape, and/or covered on one or bothsides with over layer shells to guard against piercing forces.

As shown in FIG. 10, one or more units 501 in a framework 512 may havean additional projection 513 which may be engaged or affixed to a layerof another material, depending on the application. In one application,rigid or semi-rigid plates 514 may be attached to these additionalprojections 513. In the embodiment shown, some but not all of the units501 are attached in this manner, permitting some of the units in theframework, 512 to tilt and deflect as described above when the plate 514is loaded against the framework 512. Such additional projections 513 mayallow the plates to slide relative to the framework. The plates may beremovable or permanently affixed.

In another embodiment, which is not shown, the tips or additionalprojections of some units of a framework are affixed to a flexiblematerial, such as fabric. Under load, the fabric pulls the units affixedto it, tilting and deflecting those units and other adjacent units, evenwhen the units are relatively far from the point where the load is beingapplied.

In another embodiment, the framework may be affixed or attached to theunderlying surface in portions, thereby permitting at least some of theunits to tilt and deflect under load.

It is preferable that the entire framework is made of a single material.The suitable material would be compressible, and preferably elastic. Itis also preferable to use a material which density or compressiveproperties could be varied without significantly losing its elasticproperties. Examples of suitable materials include elastomers, plasticsgenerally, organic and synthetic rubbers, and foams. A preferredmaterial for this invention is an elastic closed cell EVA (ethylenevinyl acetate) foam. However, the framework would also work if two ormore materials are combined, such as a first material for the connectingmembers, and a different material for the units, which neverthelesspermitted adjacent units to tilt and deflect under load.

The invention is preferably made in a mold, although it could be made bymachining, milling or any other suitable process. It is also preferablethat a framework according to the present invention be entirely made inone process. However, it is possible that it be made using multiplestages. For example, the connecting members and protrusions could bemolded separately from each other, or the top and bottom halves of theframework could be pre-molded, and then affixed or molded together.

As discussed above, frameworks made according to the present inventionmay be varied in many ways, including by shape, size, density, materialand configuration of the units, dimensions of the connecting members andalso configuration and arrangement of the units within the framework.Then, by choosing among these variables, the framework according to thepresent invention may be used not only as a general means to absorbenergy from impacts and vibrations, but may also be easily customised toparticular applications. For example, the framework may be designed toabsorb more energy in one particular area, and/or deflect more energy orforce to a particular area or along a particular axis.

The framework may also be configured such that all of the units areintersecting by a plane which is flat, or which is curved to fit aroundor against a three dimensional object. Portions of framework may beadhered or coupled together to accommodate three dimensional shapes, orto provide additional dampening power when layered.

Due to its characteristics, the present invention is suitable for manyapplications, including any applications requiring load bearing,vibration dampening or mitigating of forces of impact.

It will be appreciated that the above description relates to thepreferred embodiments by way of example only. Many variations on thesystem and method for delivering the invention without departing fromthe spirit of same will be clear to those knowledgeable in the field,and such variations are within the scope of the invention as describedand claimed, whether or not expressly described.

What is claimed is:
 1. An energy absorbing and transmitting materialcomprising a framework of interconnected units comprising: a pluralityof units, each unit having a base and a protrusion extending from thebase along an axis, the protrusion being tapered towards the uppermostportion of the protrusion, and a plurality of connecting members, eachconnecting member connecting one unit to an adjacent unit, eachconnecting member extending substantially perpendicular to the axes, thebase extending below the connecting members and the protrusion extendingabove the connecting members, wherein the framework is comprised of asingle elastic material throughout, and wherein, when a force is appliedto the protrusions of one or more units offset from the axes at an anglegreater than 0 degrees and less than 90 degrees, each of those unitstilts towards an adjacent unit, and wherein each of the bases is shapedto facilitate tilting or deflection of the corresponding unit against anunderlying surface contacting the bases, and wherein the uppermostportion of each protrusion is unconstrained to permit completedeflection of the units under a sufficient load so that each completelydefected unit rests on another unit, on a connecting member, or on theunderlying surface.
 2. The material of claim 1, wherein each of theprotrusions has a tip extending from the protrusion along the axis. 3.The material of claim 2, wherein an exterior surface of each of the tipshas an angle of deviation from the corresponding axis that is differentfrom the angle of deviation of an exterior surface of the correspondingprotrusion.
 4. The material of claim 3, wherein each of a plurality ofthe protrusions is conical, and the corresponding tip comprises acylinder or cone.
 5. The material of claim 1, wherein the protrusionsand/or bases are conical, frusto-conical, cylindrical, ovoid,hemispherical or polyhedral shapes.
 6. The material of claim 1, whereinthe connecting members are rods that connect units to adjacent unitswhich transmit torsion along their length, wherein each connectingmember connects directly only to two adjacent units.
 7. The material ofclaim 1, wherein each of the protrusions is conical having a radius atits base that is substantially equal to the base of the correspondingunit.
 8. The material of claim 1, wherein each of a plurality of theunits further comprises at least one base projection extending from thebase opposite to the protrusion, wherein the at least one baseprojection is shaped to minimize contact with the underlying contactsurface so as to increase the tendency of the unit to tilt or deflect.9. The material of claim 1, wherein each of a plurality of the unitsfurther comprises two or more base projections extending from the baseof the unit opposite to the protrusion and spaced apart and arranged onthe base.
 10. The material of claim 1, wherein each unit is connected toadjacent units along at least one or more longitudinal axes.
 11. Thematerial of claim 10, wherein the units are connected to adjacent unitsalong two or more longitudinal axes.
 12. The material of claim 11,wherein the units are connected to adjacent structural units along threeor more longitudinal axes.
 13. The material of claim 1, wherein at leastone unit has a width that is less than the width of at least oneadjacent unit.
 14. The material of claim 1, wherein the at least oneunit and the at least one adjacent unit have different volumes.
 15. Thematerial of claim 2, wherein the protrusion comprises a plurality ofsupports which extend from the base to support the tip.
 16. The materialof claim 1, wherein the base is an annulus.
 17. The material of claim 1,wherein the at least one connecting member is absent, thereby permittingthe at least one unit and the at least one adjacent unit to be in directcontact.
 18. The material of claim 1, wherein the material is made of anelastic foam, a polymer or elastomer, or a natural rubber.
 19. Thematerial of claim 18, wherein the material is made of a hydrophobicclosed-cell foam.
 20. The material of claim 1, wherein the units areintersected by a datum, which is flat or curved.
 21. The material ofclaim 20, wherein the units are regularly spaced on the datum.
 22. Thematerial of claim 21, wherein the units of the framework are arranged ina square or triangular grid.
 23. The material of claim 8, wherein eachof a plurality of the base projections is hemispherical.
 24. Thematerial of claim 1, wherein each of a plurality of the bases ishemispherical and the units are not hollow.
 25. The material of claim24, wherein the material is molded.
 26. An energy absorbing andtransmitting material comprising: a framework of interconnected unitscomprising: at least one unit having a base and a protrusion extendingfrom the base along an axis, at least two adjacent units, each adjacentunit being adjacent to the at least one unit, each adjacent unit havinga base and a protrusion extending from the base along an axis, the axesbeing substantially parallel to each other when the framework is atrest, at least two connecting members, each connecting member connectingthe at least one unit proximate to the base to one of the adjacent unitsproximate to the base of the adjacent unit, the connecting membersextending substantially perpendicular to the axes between the units whenthe framework is at rest the base extending below the connecting membersand the protrusion extending above the connecting members, wherein theconnecting members are elastic, and when a force is applied to theprotrusions of one or more units offset from the axis at an anglegreater than 0 degrees and less than 90 degrees, each of those units istilted towards another unit, and wherein the bases are shaped tofacilitate tilting or deflection of the units against an underlyingsurface contacting the bases, and wherein the uppermost portion of eachprotrusion is unconstrained to permit complete deflection of the unitsunder a sufficient load so that each completely defected unit rests onanother unit, on a connecting member, or the underlying surface.
 27. Thematerial of claim 26, wherein at least one unit and at least oneadjacent unit have differing densities.